NIR-active up-conversion nano-phosphors (UCNPs) based on rare earth ions doped hexagonal β-NaYF4 nanoparticles are of particular interest since they offer the highest quantum yield of up-conversion luminescence. Thus, appropriately functionalized β-NaYF4 nanoparticles can find applications in both photodynamic diagnosis and therapy. Additionally, multifunctional superparamagnetic nanoconstructs based on Fe3O4 nanoparticles (SPIONs) can be used for nanoparticles tracking with the external magnetic field, enhanced contrast in magnetic resonance imaging (MRI), as well as for diseased tissue eradication via local heating with alternating magnetic field (AMF), that is by hyperthermia.
In this work, we synthesized opto-magnetic multifunctional nanoconstructs based on lanthanide-doped β-NaYF4 nanoparticles, having sizes about 20 nm. These β-NaYF4 nanoparticles were encapsulated in SiO2. We also demonstrated that, under illumination with NIR light, the upconverting emission of β-NaYF4 nanoparticles efficiently excited molecules of Rose Bengal photosensitizer, towards reactive oxygen species generation.
The other type of nanoparticles prepared by us was superparamagnetic Fe3O4 with size from 6 to 20 nm. The hyperthermia effects were measured as a function of several experimental parameters, including: the time of application of AMF and the size and concentration of nanoparticles. The intrinsic loss power (ILP) factor was determined. The Fe3O4 nanoparticles were introduced into several types of the cells which were destroyed in alternatic magnetic field.
Combining PDT with hyperthermia treatment will allow for a more efficient cure of patients than offered by the currently used modalities. In particular, the proposed treatment is definitely less invasive than the presently applied procedures.
Audience take away:
• The implementation of showed results will make it possible to avoid obstacles encountered in traditional immunohistochemistry in cancer desease. The suppression of cell autofluorescence will be achieved by using NIR light for excitation and VIS light for detection.
• Overall, this approach will be very important for future applications in the diagnosis of metastatic diseases. In particular, the usage of upconversion nanoparticles will probably make it possible to detect single cancer cells, which circulate in the blood and are supposed to be responsible for metastasis which can be interested in audience.
• It will be also showed the possibility of eliminating cancer cells using NIR radiation through ROS generation by photosensitizers attached to the surface of the nanoconstructs. Generation of ROS can be combined with the temperature increase in the AMF (hyperthermia), which may allow more effective treatment of cancer.
• Overall, the herein proposed research on the design and characterization of multifunctional optomagnetic nanoconstructs will contribute to the field of novel approaches to efficient methods in cancer therapies and modern theranostic approaches.